Veterinary Medicine - August 2008 - (Page 438)

Copper-associated hepatopathies PEER-REVIEWED Copper concentrations of copper. Therapeutic vet> 2,000 ppm dw are thought erinary diets designed for to be directly hepatotoxic. patients with liver dysfuncHowever, some dogs may tion contain 3 to 5 ppm DMB accumulate as much as 3,500 of copper.6 Many of the therappm dw before liver pathology peutic veterinary diets also is evident.1 contain high concentrations In non-Bedlington breeds, of antioxidants and adequate copper concentrations are ofconcentrations of high-quality ten substantially lower; Doberproteins. Protein restriction is man pinschers with copper only required in dogs with heconcentrations as low as 750 patic encephalopathy, which ppm may have morphologic is a rare complication. evidence of hepatocellular Commercially available damage and show improve- 2. A photomicrograph from a liver biopsy demonstrating copcopper-restricted diets include ment with copper chelation per staining of copper-laden lysosomes (rhodanine stain, 400X). Prescription Diet Canine l/d therapy.7 This supports the (Photo courtesy of Dr. Mike Willard of Texas A&M University’s (Hill’s Pet Nutrition) and Hesuggestion that the mechanism College of Veterinary Medicine.) patic LS 14 Formula (Royal of copper accumulation may Canin). If a client prefers vary with different breeds. anti-in ammatory drugs, phenobarbital). a homemade copper-restricted diet, Interpreting the histologic ndings See Table 2 for therapy guidelines. consult a board-certi ed veterinary in these cases is an essential part of nutritionist. patient diagnosis. Important aspects Copper-restricted diet to identify are the type (suppurative Dogs with copper-associated hepatopa- Chelating agents vs. lymphoplasmacytic) and extent of thies should not be given soft water from Copper chelators reduce liver copper in ammation and the severity of ne- copper pipes.6 Foodstuffs rich in copper, content through chelation of copper crosis, brosis (bridging is worse than including shell sh, liver, kidney, heart, in plasma and tissue, which is then piecemeal), and cholestasis. nuts, mushrooms, cereals, cocoa, and excreted in the urine. D-penicillamine legumes, should also be avoided.6 In and trientine are two copper-chelating TREATMENT addition, these dogs should be fed a agents commonly used in veterinary Only treatments for copper-associated copper-restricted diet to slow—but not medicine. D-penicillamine is associhepatopathy are discussed below. In reverse—hepatic copper accumulation. ated with more side effects (e.g. vomitgeneral, provide supportive care as For growth and maintenance dog ing, nausea, anorexia, lethargy, fever, required on a case-by-case basis, and foods, the Association of American Feed skin problems) than trientine is, but it discontinue any drug that is known to be Control Of cials recommends 7.3 to may also inhibit brosis by preventpotentially hepatotoxic (e.g. nonsteroidal 250 ppm per dry matter basis (DMB) ing cross-linking of collagen and by TABLE 1 Laboratories That Perform Heavy Metal Atomic Absorption Analysis Laboratory and Test Name Michigan State University Diagnostic Center for Population and Animal Health Test: Trace nutrient minerals–tissue Colorado State University Veterinary Diagnostic Laboratory Test: Copper Sample Requirements Fresh or freshly frozen tissue; 50-mg minimum sample size in a leakproof, rubber-free container Fresh tissue is preferred but may be ﬁxed or retrieved from block; three 1-cm-long needle biopsy pieces Contact Information DCPAH 4125 Beaumont Road Lansing, MI 48910-8104 (517) 353-1683 Veterinary Diagnostic Laboratory 300 West Drake Fort Collins, CO 80523 (970) 297-1281 438 August 2008 VETERINARY MEDICINE

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Veterinary Medicine - August 2008 Contents Editors' Note Leading Off ClinQuiz Idea Exchange Practical Matters Diagnosing and Treating Canine Copper-Associated Hepatopathies Canine and Feline Demodicosis CE Form Advertiser Index Product Preview Marketplace/Classifieds Mind Over Miller

Veterinary Medicine - August 2008

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